Modeling bat activity across the fire-managed landscape of Mammoth Cave Nat’l Park using remotely-sensed forest canopy data

Dodd, L.E.1, M.J. Lacki1, N.S. Skowronski2, M.B. Dickinson2, & L.K. Rieske3 1Forestry Department, University of Kentucky2Northern Research Station, US Forest Service 3Entomology Department, University of Kentucky

Remote Sensing & Wildlife

• Large-scale patterns1

• Feasibility • Necessity

1 Vierling et al. 2008. Frontiers in Ecology & the Environment 6: 90-98. Hudak et al. 2009. Remote Sensing 1: 934-951..

Bats at Mammoth Cave • Variable foraging & habitat use across species1

• Prey availability & forest canopy structure

• White-nose syndrome• Now at Mammoth Cave; changing predator-prey dynamics?

1Swartz et al. 2003. Pp. 257-300 in: Bat Ecology. Lacki et al. 2007. Pp. 83–128 in: Bats in Forests: Conservation and Management

Core Hibernacula

- 2004

- 2005

- 2007

- 2009

- 2008

- 2010

Burn Areas

Mammoth Cave Nat’l Park

Core Hibernacula

- 2004

- 2005

- 2007

- 2009

- 2008

- 2010

Burn Areas

Survey Transects, Aug 2010 onward

Mammoth Cave Nat’l Park

Core Hibernacula

- 2004

- 2005

- 2007

- 2009

- 2008

- 2010

Burn Areas

Survey Transects, Aug 2010 onward

Mammoth Cave Nat’l Park

Methods

Methods

MethodsBat Activity

• Zero-crossing acoustic surveys• Spanning 2010-2012 (still ongoing)

• 170 nights (1,086 detector / nights)• Emphasis on April-May, Aug-Oct

MethodsBat Variables

• Echoclass v.1.11

• High freq (> 34 kHz) • Low freq (≤ 34 kHz) • Feeding buzzes

1USFWS. Indiana Bat Survey Guidance. http://www.fws.gov/midwest/Endangered/mammals/inba/inbasummersurveyguidance.html

MethodsBat Variables

• Echoclass v.1.11

• High freq (> 34 kHz) • Low freq (≤ 34 kHz) • Feeding buzzes

Total Activity

1USFWS. Indiana Bat Survey Guidance. http://www.fws.gov/midwest/Endangered/mammals/inba/inbasummersurveyguidance.html

MethodsLiDAR Survey

Figure by Renslow

• LiDAR = Light Detection and Ranging • Discrete-return scanning LiDAR1

• 900-1,600 nm wavelength• > 4 pulses / m²

1Skowronski et al. 2007. Remote Sensing of Environment 108: 123-129.

MethodsLiDAR Survey

Figure by Renslow

• LiDAR = Light Detection and Ranging • Data collected Fall 2010 (leaf-off) via fixed-wing aircraft

MethodsLiDAR Variables

• What scale is meaningful?

MethodsLiDAR Variables

1Lesak et al. 2011. Remote Sensing of Environment 115: 2823-2835

• Laser returns across over-, mid-, & understory strata1

Under

Mid

Over

MethodsLiDAR Variables

15 m

• Laser returns across over-, mid-, & understory strata1

•15 m radii around survey points1

1Lesak et al. 2011. Remote Sensing of Environment 115: 2823-2835

Under

Mid

Over

MethodsLiDAR Variables

• Strata (absolute & relative)• Over-, mid-, & understory

• Determining canopy shape• Mid:Over, Under:Mid, & Under:Over

MethodsLiDAR Variables

• Strata (absolute & relative)• Over-, mid-, & understory

• Determining canopy shape• Mid:Over, Under:Mid, & Under:Over

• Gap Index• Percentage of pixels with no laser returns >3 m height

• ANOVAs for site, temporal, & fire effects

Analysis & Results

• ANOVAs for site, temporal, & fire effects• Multiple linear regressions relating activity to forest veg

• Response variables: - high freq pulses - low freq pulses - feeding buzzes

• Predictive models: - understory - midstory - overstory - “total” clutter

• Model selection using Akaike’s Information Criterion• Models in SAS 9.0, then protocol of Burnham & Anderson1

1Model Selection & Multimodal Inference, 2nd Edition

Analysis & Results

Site, Season, & Annual Effects

Site, Season, & Annual Effects

• Unsurprisingly, lots of variation across sites!

Site, Season, & Annual Effects

Far fewer replicates (n = 6)

Site, Season, & Annual Effects

Site, Season, & Annual Effects

Site, Season, & Annual Effects

High Freq: F2,1083 = 3.6, P = 0.02Low Freq: F2,1083 = 29.2, P < 0.01

A A B

a b c

Site, Season, & Annual Effects

Site, Season, & Annual Effects

A B B

a b ab

• No apparent WNS impacts in 2012…

High Freq: F2,1083 = 4.1, P = 0.02Low Freq: F2,1083 = 3.0, P = 0.05

Site, Season, & Annual Effects

Site, Season, & Annual Effects

• Sites surveyed in Fall 2010

Effect of Fire

Core Hibernacula

- 2004

- 2005

- 2007

- 2009

- 2008

- 2010

Burn Areas

Survey Transects, Aug 2010 onward

• Repeated visits have created a time-series…

• As with sites, lots of variation across years since burn!

Effect of Fire

Effect of Fire

Far fewer replicates (n ~ 5)

Effect of Fire

Far more replicates (n > 200 each)

Effect of Fire

High Freq: F2,1083 = 11.1, P < 0.01Low Freq: F2,1083 = 1.0, P = 0.37

A B B

Effect of Fire

A B B

Feeding Buzzes F2,1083 = 11.1, P < 0.01

Effect of Fire

Effect of Fire

Core Hibernacula

- 2004

- 2005

- 2007

- 2009

- 2008

- 2010

Burn Areas

Survey Transects, Aug 2010 onward

Effect of Fire

Analyses pending

Effect of Fire

Analyses pending

Effect of Fire

Analyses pending

Effect of Fire Relation to Canopy Clutter

• Data within first year of burning (2010-2011)

• High frequency echolocators negatively associated a cluttered understory

• Low frequency echolocators negatively associated with a cluttered understory & overstory

• Feeding buzzes negatively associated with a cluttered understory & overstory; positively associated with canopy gaps

Low Frequency Bat ActivityPredictive Map – Total Clutter

Discussion & Implications• Activity lower at burned sites, but models suggest activity is also positively related to less-cluttered canopy conditions… • High frequency & low frequency echolocators both respond to differences in clutter… And are relatable to management!

• How does this relate to longer-term fire management plans?

• Funding– Joint Fire Science Program

• NPS Personnel– Dr. Rick Toomey– Steve Thomas– Shannon Trimboli

• Tech Support!– Tracy Culbertson– Stella James– Klint Rose– Jennifer Winters

Thanks!